The shooting stemmed from a fight among some casino visitors, and a Potawatomi spokesman told WISN 12 News that a security officer tried to break it up before the shots were fired.

"As our security officers are instructed to do, she intervened. She was knocked down, incapacitated. She called for backup," Amundson said.

But other security officers were tending to a medical emergency in another part of the casino, leaving casino guests to try to wrestle the gun from the gunman.

"We need to get that gun because there was still two guys on the floor fighting over that gun," said De Von Dent, who confronted the suspect.

"I had to get the gun. I already saw that somebody was shot and that could have been my friend. That could have been anybody. I had to get the gun from him," said Antonio Felder, who confronted the suspect.

They questioned the lack of action by casino security, but the spokesman said the casino believes its security personnel acted appropriately.

"It's not an armed team of security officers. Their job is to identify a threat, keep people away from that threat, move away from the threat and then become witnesses themselves until police backup arrives," Amundson said.

Casino officials told WISN 12 News they are taking the matter very seriously as they re-evaluate their security procedures.

But it does have the popular tribal casino rethinking its safety procedures. Amundson said new steps are being considered to ensure this type of incident won't happen again.